Contents lists available at ScienceDirect Forest Ecology and Management journal homepage: www.elsevier.com/locate/foreco Contrasts in xylem hydraulics and water use underlie the sorting of different sand-fixing shrub species to early and late stages of dune stabilization Xue-Wei Gong a,b , Jing-Jing Guo a,b , De-Ming Jiang a , Xue-Hua Li a , Fabian G. Scholz c , Sandra J. Bucci c , Guillermo Goldstein d,e , Guang-You Hao a, ⁎ a CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China b University of Chinese Academy of Sciences, Beijing 100049, China c Grupo de Estudios Biofísicos y Ecofisiológicos, Instituto de Biociencias de la Patagonia, Consejo Nacional de Investigaciones Científicas y Técnicas and Facultad de Ciencias Naturales y Ciencias de la Salud, Universidad Nacional de la Patagonia San Juan Bosco, Comodoro Rivadavia 9000, Argentina d Department of Biology, University of Miami, P O Box 249118, Coral Gables, FL 33124, USA e Departamento de Ecología Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Nuñez, Buenos Aires C1428EGA, Argentina ARTICLE INFO Keywords: Desertification control Drought Embolism Sap flow Vegetation succession Water use strategy ABSTRACT Dominating sand-fixing shrubs play crucial roles in the stabilization and rehabilitation of sand dunes. Different sand-fixing shrub species often separate along the temporal-spatial environmental gradient during the sand dune stabilization process; however, the physiological mechanisms underlying such a separation remain poorly un- derstood, which limits our ability to identify the causes of land desertification and the cruxes of rehabilitation. We investigated xylem hydraulics and water use characteristics of four important shrub species used for sand dune fixation projects in northern China that show distinct preferences to different stages of dune stabilization, i.e. two species succeed in active dunes and the other two in fixed dunes. The major aim was to examine the roles of xylem hydraulics, water use and the coordination of these two aspects in determining the habitat preferences of sand-fixing shrubs along the process of dune stabilization in water-limited environments. The two active-dune species consistently exhibited higher stem hydraulic conductivity but lower resistance to drought-induced xylem embolism than the two fixed-dune species, which reflects contrasting requirements to shrub hydraulic func- tionality in sand dunes of the two successional stages that differ substantially in soil water regimes. In co- ordination with contrasts in hydraulics, they also diverged clearly in water use strategies with the fixed-dune shrubs showing more conservative water use. Our results highlight the critical roles that hydraulics and water utilization play in determining the adaptation of dominating sand-fixing shrub species to their respective en- vironments shaped by the plant-soil interactions during sand dune vegetation development. 1. Introduction Vegetation restoration is crucial for sand dune stabilization and rehabilitation resulting in higher plant biodiversity, soil fertility and ecosystem productivity and eventually turning formerly bare mobile (active) dunes into vegetated stabilized (fixed) dunes (Zhang et al., 2005; Zuo et al., 2009, 2012). Sand-fixing shrubs, usually xerophytic species that grow on water-limited inland sand dunes, play an irre- placeable role in stabilizing the dune systems (Zhao et al., 2007; Liu et al., 2008; Qu et al., 2017). At the early stages of dune stabilization, rapidly-growing pioneer shrub species initially establish in the bare sand soil and create a preferable condition for the colonization of later- successional shrub species by stabilizing the drifting sand and increasing the soil nutrient availability (Zhang et al., 2005; Zhao et al., 2007). With the vegetation development, active dunes can be pro- gressively restored to fixed dunes, during which the later successional shrub species gradually dominate the community while the pioneer shrub species exhibit decreasing ecological performance and finally withdraw from the community (Ranwell, 1960; Zhang et al., 2005; Zuo et al., 2009). Owing to higher vegetation cover, it is assumed that fixed dunes lose more water through canopy transpiration than active dunes and hence have lower soil water availability to plants (Gupta, 1979; Li et al., 2007; Kutiel et al., 2016). It has been shown that terrestrial woody plant species cope with different soil water regimes by discreetly regulating the balance of soil water supply, xylem water transport and leaf water use (Torres-Ruiz et al., 2013; Aguilar-Romero et al., 2017). https://doi.org/10.1016/j.foreco.2019.117705 Received 24 July 2019; Received in revised form 18 September 2019; Accepted 19 October 2019 ⁎ Corresponding author. E-mail address: haogy@iae.ac.cn (G.-Y. Hao). Forest Ecology and Management xxx (xxxx) xxxx 0378-1127/ © 2019 Elsevier B.V. All rights reserved. Please cite this article as: Xue-Wei Gong, et al., Forest Ecology and Management, https://doi.org/10.1016/j.foreco.2019.117705